


Thirsting for you

by FormSans



Category: Undertale (Video Game)
Genre: Alternate Universe - Vampire, F/M
Language: English
Status: In-Progress
Published: 2020-07-06
Updated: 2020-08-04
Packaged: 2021-03-05 01:20:04
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 3
Words: 5,280
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25106074
Author URL: https://archiveofourown.org/users/FormSans/pseuds/FormSans
Summary: You were just an average human in a city where life was hard. Being an introvert didn't help with making friends. Then one night, one mistake, you ended up getting the attention of a certain skeletons. A skeletons that loves the smell of your blood. Something in your chest pounding loud in your ears when he is close. But it isn't your heart, that felt ice cold.
Relationships: Alphys/Undyne (Undertale), Asgore Dreemurr/Toriel, Chara/Frisk (Undertale), Mettaton/Papyrus (Undertale), Sans (Undertale)/Reader
Comments: 18
Kudos: 123





	1. Those red eyes

**Author's Note:**

> Trying my own idea for a Vampire Sans.
> 
> Comments and opinions are very much welcomed. I just hope it will be decent enough.

It was a cool night out, the stars peeking from the slightly clouded sky, the crescent moon gleaming above. The park you were walking through seeming to be calm and quiet, insects buzzing off from the trees and the wind blowing through the leaves. Your hands bring the thick zipper jacket tighter around you. Giving a shiver as the cool air attacks your flushed cheeks.

In what good mind did you have to try to go out to a bar to hopefully catch a date? It was late Saturday night and you had come to attend a group that was posted on Bookface. A meet and greet group. You had wanted to try to gain some friends or maybe even a boyfriend there. Being an introvert that mainly concentrates on work, anime or playing the games you enjoy. Not being a social butterfly and without any friends from your childhood meant you were alone. Renting a tiny apartment in the more shady part of the city meant you didn’t get out much.

Tonight had been a failure. Having come at 6 in the afternoon for the start of the club. Meeting a few guys and gals but they all seemed to have their own groups already. Trying to sit at a booth and introduce yourself ended up with you getting glares and ignores. Those that didn’t ignore you were the ones that were half drunk already and were trying to get in your pants, part figuratively and the other literally. Having a male or even a female trying to slide their hand down your pants is not that great.

It was 11 by the time a woman got enough with you trying to be friendly and tossed a strong drink at you. That was when you had enough, left the meetup group and stormed out. The partially drenched coat making the cold wind hit harder. Deciding to take a shorter route home, you decided to go through the haunted park.

Named so because it was the park that has had people go missing, some showing up looking like a raisin. The news seems to love giving warnings and coverage. Most stay clear of it during the day. No one goes at night, not when that is when the kidnappings are believed to happen. All reports of those having left after the sun sets, routes going through the park. It always seemed to be when one person was walking, rare for it to happen when two or more are walking through.

There had been one case where a person had been running out and started screaming of a demon chasing them, having gotten their friend. The person being covered in blood and wounds over their body. No matter how much time had passed, they kept claiming a demon or devil had flown through the trees and had attacked them, ripping the throat out of their friend’s throat and had been drinking their blood before turning to the person, the person having started running. The demon managed to get a few attacks in but backed off once they passed the park borders.

Then one might ask why a woman in their 20’s would be walking through the haunted park alone and near midnight. Well this woman was cold and getting colder and might not survive a full 2 hours of walking back to their shitty apartment while the slightly wet clothes made it colder. Hypothermia is a possibility, and you didn’t want to be shivering when you get home. Going through the park cut the time down by half. It was a massive park that is seated between the shady part of the town and the more cleaner area.

Eyes peeling for the trees and bushes. Not fully sure if the story is real but it was a better guess than anything else right now. A loud snap made you squeal and turn to where the sound came from. Only to find a black cat with white ears looking up at you with a broken branch under their front left foot. Holding your chest as you take a few seconds to calm. The cat in the meantime got up and strutted off into the bushes as if they didn’t just give a human a near heart attack.

You give a chuckle at how jumpy you were. There didn’t seem to be anything. Starting on the trek home, you began to relax. Maybe the kidnapper or killer wasn’t there tonight? Maybe there is no killer or kidnapper. Thoughts of maybe the story being fake and just to get people to vacate the park or just something to get news circling. Smiling at the thoughts and getting stuck in your head, you ignored the extra drop in temperature.

There was a second snap, flinching but not making a sound, you turn slowly and smile. Wondering if the cat was following you and trying to scare you. Only for your smile to drop when two big red eyes seem to glow from the darkness. One being bigger than the other. The left one being a small pin prick dot, like from a laser pointer almost. The right though, it almost looked like a light flaming ball with a cat slit pupil going up and down the middle.

Fear coursing through you as the idea of a demon wasn’t sounding as far fetched now. Body shivering violently both from the fear and from the freezing temperature. Taking a step back as the lights suddenly disappear. Fear freezing you to the spot. Legs not seeming to move as your mind yells at you to run. Breathing coming out in quick huffs.

Suddenly a rustle and a black figure suddenly rushed at you. Features being too fast to see. Clamping your eyes closed, you wait for whatever it was.

Only to feel a weight on your shoulders, warmth and then nothing. Slowly opening your eyes, the area seemed calm and peaceful again. Bugs buzzing and chirping. Wind blowing. Hands moving up and feeling fabric there, you notice an unzipped biker jacket with little spike studs on the shoulder pads and the entire jacket being pitch black.

Confusion on your features as you look at the jacket and then around. Not seeing any eyes or figures, your body finally starts listening to your brain. Turning and starting to move in a power walk through the rest of the park. Wanting to forget it. Hands unconsciously gripping the edge of the jacket tighter, the cold seeming to not affect you anymore.

Steps sounding so loud as you made it to the other side, stepping on the road and crossing the street. No cars roaring around as your feet made fast work of the route back home. Not stopping as you start to climb the stairs to your level and then getting your keys from your pocket and unlocking the door. Slamming it shut. Leaning on the door as you slide down and just stare ahead.

Your brain does not seem to even register that you are home. It being so blank. Gripping the biker jacket tighter, enough to turn your knuckles white. Your mind races with what happened.  _ Was that the demon? Why was I given a jacket? Was it because I was cold? _ When no answers seemed to come, you slowly struggled up. Slipping the jacket off and looking at it. It had felt so warm. Bringing the jacket closer to your face, a strong smell of iron comes from the interior.

Scrunching up your nose, you hold it away before going over and hooking it over one of your dining chairs (Not that you can have a large table in this space) before looking around.

The dining and living room combines with the open way kitchen and the front door. A doorway leading into the hall that has a bathroom, toilet and your own bedroom. Wasn’t anything big and the pale blue wallpaper was peeling off the concrete walls. It had always made you think that this building was built when they used actual concrete and supports for the apartments, not the paper thin walls. It was a blessing and a curse. Not able to hear noisy neighbours but also means no one can come to your aid if you are being murdered. Not a pleasant thought.

Taking a sigh and one last shiver, you head for the bathroom while stripping off the alcohol covered jacket of your own and putting it in the hamper that was just a basket in your living room. Going into the grey old bathroom and turning on the shower on hot while you undress. Stepping in as the steam fills up the bathroom. Not bothering to close the door when you lived by yourself.

Letting the scalding hot water run over your skin as you felt your very bones remove the ice that had settled in them. A smile on your face as you began to lather up on the cheap body wash and slide it over your skin. Mind playing in your head the odd red lights you saw in the darkness. From the corner of your eye, you almost swear you could see them in the bathroom with you. Snapping your head to where you thought you saw them, only to see nothing but the steam from the shower.

Suppressing a shiver, you rinse yourself much quicker than you were with washing yourself. Grabbing the towel and drying yourself before almost running to your bedroom. Getting into your winter sleepwear. Walking the towel back to the bathroom and getting a glass of water. Glancing around your small apartment before you noticed something that made you put the glass down and run to your room in hopes of being in a safe place.

The jacket that you had put on the chair was gone and a single daisy on the table in front of were it was.


	2. Brand new day

Paranoia was a serious thing, feeling like someone was able to get in without a sound or breaking anything. After a rough sleep and nightmares of those red eyes, you came out to check the house, finding no broken locks or damage. Nothing else was taken either. Only the taking of the jacket and then the gift of the flower. Unsure of what to do with it, you put it in a vase. If the person could get in, they might become violent if they find their ‘gift’ in the trash. The fear of having them attack you while you sleep was very real.

There had also been a toss up of calling the police or not, but the fact of no real evidence and nothing damaged would brush them off. So staying quiet and trying to hope that the person won’t do anything unsavoury is the best option, even if it causes a fair bit of anxiety.

Eventually you got your clothes on for your work. Taking your work satchel, that was more for when you get free time than anything, and closing the door. Skipping breakfast as your stomach felt too upset to eat right now. Walking fast and head low as you exit your apartment building. Instantly, it felt like there were eyes on you. Giving a shiver, you start to head off. Looking around to see if there was anyone out here, but came up with nothing. There was barely anyone out in this part. Avoiding the park with even more effort than before, like it was the plague.

Try to keep to yourself as much as possible as you begin to make your way to the much cleaner parts of the city, more people starting to mill about. It was mid-morning at the moment, the sun starting to heat everything up. Eventually you make it to your destination. A second hand shop that sold books and takes books that people bring in to sell. The front being glass that was only showing piled books to attract visitors. A frame around the wooden door and large windows for those to easily see through. The walls coloured a maroon with the sign that says ‘ Second-Handy Books ’ in deep blue writing on an orange board. A house like roof with the shop being only one story high.

Moving in as the sensor above the door rings out as you pass through the door, you avoid a stack of books to head for the back. The boss’s voice rang out, “Finally cupcake! It was feeling lonely here!” Making you laugh as you turn to find the person in question.

Your body relaxes as you go to put your satchel in the lockers for the workers while you huff out, “Yeah, and let you turn every girl away from buying, no way Buttface!” Laughing as he acts mock offended.

Dramatically leaning on you like he was feinting, “Oh, that hurts Cupcake. What have I ever done to deserve such mean words?” Acting like a true drama queen.

You shove him as he falls to the ground in a huff of laughter while you snap back, “Maybe make a teenage girl run in terror from the bookshop because of your dreadful flirting. Buttface!” Getting your tag from the board where tags were put after a shift. Tagging it to your shirt before turning and giving your boss and step-brother a playful glare.

He starts laughing as he lifts his hands in surrender as he stands, “Okay okay Cupcake. I get ya. I try to hold back on my natural charm that the ladies just can’t handle so far.” Rolling your eyes, you move to start getting the newly arrived books to the shelves where they belong.

Your brother follows, only to go to the counter which he mans. Both of you doing your work, your mind only concentrating on finding the genre of the book and then looking at the last name of the author to find where it should be placed. The next thing to look for is if there are any series the book belongs in and sliding in where it should. The previous events are already being drone out by work.

A ring of the bell was barely registered, but the flirting from your brother did, “Heya sexy. I’m  Rodger and I think I am the man of your dreams.” Snorting as you can see inside your mind of him giving finger guns to the poor woman with a wink. Debating on whether you should try to rescue the poor woman on the other side of his terrible flirting.

Only for the voice to realise she has it under control, “Hah. Nice try Punk, but I already got a wife. And if I were looking, you would be the last one I would ever dream of. Maybe if I was having a nightmare! Hah!” You snort out laughing.

Doubling over as you call, “Damn boss! That is a solid burn!” Laughing as you continue on, ignore the conversation. Already seeing in your mind of his flushed but smiling face. He loved it when the girls gave him sass. Loves it more than when they actually enjoy it. Also helps that your brother is gay.

Moving through the shelves as you keep going, taking a new stack of books in your left arm once you put the previous back. Using your right to pick up a book and continue on.

Without realising, a shadow looms over you. Without the light making it harder to read the title. Making you turn to see a tall woman with pure fire red hair pulled into a ponytail, skin fairly tanned, like she works out in the sun a lot. Left eye covered by an eye patch and the right eye a blazing golden colour (From her perspective). The woman giving a large smile as she holds her hand out, “Nice to meet ya Punk! I’m Undyne. Hoping you could help me find the right section. Your boss told me to ask you. I want the paranormal section.” You grab her hand, after putting the book you were holding in your right back on the pile, only for her to hold it with such strength and shake it hard. Enough to make your body tremor and your hand be filled with pain.

You look at her arms to see that she had a long sleeve black top on and old jeans. You are sure she has more than enough muscles under there for two people by how hard she held your hand. Her smile wide and for a second, you thought you saw the canine teeth longer, thinking it was the trick of the light.

Smiling, you give a nod and gesture for her to follow you once you let go, “Sure, this way Undyne. We don’t have too much but you might find some of interest. I hope you do. These books can be quite interesting.” Dropping the books in your arm in an unsorted pile before leading her through the maze like shelves to the section.

Her voice piping up, “You read them?” So simple but you feel it had a deeper meaning.

Giving a nod as you stop in front of the hanging sign above the shelves that read ‘Paranormal’ to help those to see it, “Yeah. I find the story of ghosts, werewolves, vampires and such interesting.” Giving a shrug, “Just a taste I enjoy.” Getting ready to let the woman be, only for her to roughly pat your back with a smile.

Almost seeming relieved, “That is great Punk. Oh, never did get your name. Maybe we can exchange numbers, I like ya Punk and would love to have you as a friend!” It almost sounded forced or a different meaning behind it. You keep your face as neutral as you can as you turn.

Trying to give a small smile, “Sorry, on the clock. Maybe after my shift we could. I am (y/n) by the way. I will get out of the way.” Turning and going back to work, almost missing the scroll on her face.

Getting back into the mindset of sorting the books out. Not too long did you hear another ding from the door. Not even trying to find out if Undyne left or not as you had work.

The Buttface not seeming to be talking loud as he seems to be in conversation with someone. If it wasn’t loud, then it wasn’t flirting. That was enough for you to not care that much. Then the feeling of those eyes again came. Giving a shiver, you almost feel a presence behind you.

Whipping around, you find a man that was just bigger than you, ice blue eyes, rust like brown hair and skin so pale Dracula might be jealous. His head gazing down at you and a large smile on his face. Soon you realised he was holding out a hand as his deep voice came out, “Heya pal, my name is Sans. Nice to meet ya. Say, could ya help me find the paranormal section?” You thought you almost  _ felt _ the power coming off of him. The air feels ice cold.

Then his words ring in your head. A  _ second _ person looking for the paranormal. You arch an eyebrow which he copies. Then looks at his hand then back at you. Realising you hadn’t taken his hand. You slowly reach out, “I am (y/n) And sure I can help.” But as soon as you touched his skin, you felt cold, like an ice bucket had been thrown at you. Your vision starts to swirl as you drop the books in your left arm. A look of panic on his face as you feel your body going limp. Seeing his hands reach out for you as the world began to fade to black.

You almost swore his hands suddenly turned into snow white skeletal hands, before the darkness consumed your consciousness.


	3. Sans's declaration

**Notes for the Chapter:**

> Part of the idea in this chapter was thanks to Of Spells and Illusions by charamelwrites. This is an amazing fanfic you guys should try.

Feeling something wet on your head and some softness under you. Giving a groan as you lift your hand to where the wetness is to find a face washer. Opening your eyes to look at it.  Rodger ’s worried voice pops up, “Thank goodness Cupcake. You had me terrified. You suddenly collapsed right in front of a customer. He just came in holding your passed out body.” YOu look at his worried face as his voice starts to turn to a teasing tone, “I never knew you to fall for someone so quickly.” It was obvious that he was trying to make some light of the situation.

You huff in a laughing manner as you sit up. You were in the spare room that is the little attic space. Rodger had put a bed and some beanbags for when or if either of them needed some time to relax during a shift. In this case, it was for when you passed out. Her mind blurred on what happened. You wanted to get to understand, “What happened? I remember talking to another new customer and I shook their hand and then everything went black. How long have I been out?” Handing him the wet face washer to hold your head as a migraine was very much pounding in your head.

Rodger sighs, “A few hours. I closed us for the lunch hour. Sans, the guy that was there, hasn’t left since you fainted. Even offered to walk you home. Not sure how I feel about that though. For now, you rest. I might make you take the week off with pay. Ah. Before you say anything, as I see the angry look on your face, you have been working here without a proper day off. I barely got you to take extra hours off on afternoons you wanted to go to those meet ups with.” He puts his hand on your head with a sad look.

You were upset. Working here felt amazing. A great boss and usually didn’t have that many problems. Was just a sacrifice of a lot of potential social interactions. You never minded that before. One look at Rodger’s face and you knew this was not something up for discussion, “Fine! I can tell when it is a losing battle. Geez.” Sighing as you lay back and look at the ceiling, “What about that Sans guy? It is sweet he is concerned about me but seems weird for someone to be so concerned for a person they literally only shook hands with.” Though this worry that is knotting in your stomach that the guy was too suspicious and there was something up with him.

Without warning, Rodger drags you into a hug, “Come on Cupcake. I might not be your brother by blood but you are still my  little sister . Stay safe. Be cautious.” His hold tight, as if he was worried you would disappear in his hold. You return the gesture. It isn’t the first time you fainted. But the first time during work. The others had been after your shift and after you had been having little to no sleep. Sometimes looking pale enough to be a corpse. You couldn’t be too angry with him being concerned.

Grumbling you gently push him away, “Fine fine. You better get ready to open after lunch hour. And maybe finally hire someone else.” He has always been stubborn to not hire anyone else, but with you having a week off, he will have to. He laughs as he leans back and lets you go. Giving his usual winning smile, the one he doesn’t show for anyone but her, until he gets a boyfriend that is.

From there he explained when you were to come back for work and not to come beforehand. Getting her some water and letting her have her lunch before you leave the shop. Within seconds Sans was in front of her, still human looking hands, with worry on his face, “Hey pal, you doing alright? You gave me quite the scare.” You notice his outfit. He had a black zipper hoodie with big pockets, when he has his hands stuffed in, with long black jeans and black sneakers. He seems to like black.  His hair pulled back into a ponytail, his hair being long enough to be pulled back and have some hanging down from the hair tie .

Looking at him with a suspicious look, “Yeah, I am. Say, why are you worried about me? I mean, we just met.” You weren’t going to try to be sly and find out. Get straight to the point. Showing that you didn’t trust this Dracula wannabe.

He chuckles, “Don’t beat around the bush, do ya? Well, do you believe in soulmates?” His looks relax into what one might see as lazy. Shoulders seem to ease into a slump as he watches you. His eyes almost seemed to flash red for a second. But looking into his eyes shows blue, must be your imagination.

Rolling your eyes, “Not really. I kind of grew out of that. And if they are real, how would one even know? Isn’t like you can just ask your soul who your mate is.” Crossing your arms as you start to head off to the shops, not wanting to walk home. Just as you expected, he started following you. Confusion flashed on his face before the lazy look was back.

“Actually you can. A friend of mine actually works with souls. They are a real thing. Not what you expect. Looking like the valentines heart shapes with colours. But it is an actual thing. It was why I wanted to look at paranormal, see if it matches what my friend’s theories are. Though it seems that after you fainted and was taken away from your boss, I managed to find it but the one that I wanted was already sold out. And by that look I saw when I asked, means someone else got to the punch before me. I think I know who. Has always been a little rival of mine. Anyway, getting off topic. I can actually get my friend to show you. Though I can already tell you that I know you are my soulmate.” Oozing confidence. Like this was meant to woo you.

You give him an unimpressed glare before walking into the shops, heading straight for the grocery section. You might as well stock up on a few more things. He was relentless as he seemed more than happy to follow you. Sighing, “Listen, I just can’t believe that stuff. I don’t know you and frankly, have no interest in knowing you.” You just entered the fresh produce section but you felt like it just dropped a few degrees. Are they trying to keep the fresh produce in a cooler section or something? “You seem way too creepy with your direct interest when you don’t know me. Never mind the bad vibe you are giving me. So please, leave me alone.” You felt him start to lag. You didn’t bother to look at his expression.

Not the first that thought they could just insert themselves into your life. You have just gotten sick of it. Better to push the person away than have to deal with a thousand more assholes that think they own you. Life has always been like that. You used to give the benefit of the doubt but after the twenty males and females that used your trust to try to be the ‘alpha’ over you. Just because  your parents were some big shots in society . So that drew some unsavoury people while you were growing up. Now you have become always suspicious, especially if they know your parents.

Rodger was stronger and able to better judge people than you were so he wasn’t affected by those people. He was more than happy to settle with a smaller job away from his parents, and you were more than happy to follow him. Able to get away from that crowd. Didn’t mean that those people didn’t occasionally didn’t come and make your life as difficult as possible.

Without feeling him near you, you felt more comfortable getting some of the things you need. Some fruit for when you wanted to snack, some more meat to cook up, some ingredients to make bigger meals and some treats for yourself. Even let yourself buy a movie that was discounted. Going to the counter without seeing or hearing from Sans. Getting your items bagged up before you started to make your trek home. Double checking that Sans wasn’t following. The sun setting low over the sky.

You began to get close to that park again, you eagerly avoided going in with the preference of going around. Only for that plan to be interrupted when an arm grabs yours and drags you in. You were about to make a complaint, only to see a pissed off Sans. Struggling as you began to snarl out, “What the hell? Fucking let me go? This is what I meant, asshole.” His strength seemed to be much more than your own. He stopped when it seemed we were near the centre. The sun has dipped down over the horizon to give a beautiful end to the sun set.

He lets go and glares at you with red eyes. Wait, that makes you flinch back as deep red eyes were glaring at you. His teeth showing in his snarl, “No way am I letting my soulmate leave that easily. I took you here to prove it. As, only my soulmate can see my true form when I am blending in.” His face relaxing and the blue coming back as he offers his hand, but for you to put your hand on instead of a handshake, “Let me prove it. If you hold my hand, not only will you see my true form but our souls will come out. A white string between to show that we are soulmates. If I can’t convince you to visit my friend to show, then I will get right to the point. I have been waiting for over a thousand years to meet my soulmate.” His face softening as he stares at you like you are the most precious thing.

You look around in the calm park before looking at him. Uncertainty flowing through you. Slowly putting the shopping bags down, you reach out and grab his hand. Gasping as his form suddenly weavers and there was a skeleton with glowing red eye lights in the large round void of his eye sockets. His skull smooth with his mouth seeming like normal lips instead of a jaw. Sharp overhanging fangs in his mouth that went over his bottom teeth and a tiny big of his bottom bone lip. His hands being skeletal, like you saw before you passed out. His bones being whiter than any snow that could have ever been seen before. His hands felt so frosty and cold.

But that wasn’t what made you gasp lighter. It was the thing that was right in front of your chest. The look hypnotises you as you stare at the glowing heart. The colours seemed to swirl around like it was a living thing. But then there was the white cord that seemed to go from your heart to his, which was a dark red and upside down compared to your. Yours being a green with blue in a swirling smokey pattern. The heart looked dull in colouring, especially compared to his.

His voice sounded so close as you stared at your ‘soul’, “I finally found you, my sweet mate.” As darkness began to surround you.


End file.
